Generally, food waste treatment is very difficult. That is, it is difficult to incinerate food waste or to bury the food waste in landfills because it contains a large amount of water. Further, standards for food waste treatment are becoming strict.
An example thereof is the regulation on food waste sorting and discharge. According to this regulation, food waste must be separated from other waste and discharged using a separate food waste bag. Even in this case, since the food waste contains a large amount of water, it easily decomposes in a food waste bag, thereby causing odor and polluting the surroundings with leachate.
In the ideal food waste discharge state, the food waste contains almost no moisture. However, it is difficult to completely dehydrate food waste using recent technologies.
Further, even though food waste contains many valuable contents worth recycling, the food waste is generally buried as it is because it is very difficult to treat and separate the valuable content from the food waste. That is, although the food waste can be used as feedstuff for animals or as compost after treatment that includes steps of pulverizing, drying, and mixing the food waste with other material, the food waste is generally discarded without being reused.
Accordingly, in order to reuse the food waste from houses and restaurants, the food waste must be discharged in a dehydrated state.
In consideration of the above problems, several kinds of food waste treatment apparatus have been developed.
One example of a conventional food waste dehydration apparatus is disclosed in Korean Patent Application No. 10-1997-0081044, and uses microwaves. The food waste dehydration apparatus includes a dry compartment having a space in which food waste can be stored, pulverized and dried, a rotating axis installed in the dry compartment, a mixing blade rotating along with the rotating axis, and a magnetron for heating food waste in the dry compartment. However, this apparatus has a disadvantage in that it takes a long time to dry food waste and it cannot dry food waste continuously.
A further dehydration apparatus entitled “a coating liquid drying apparatus using microwaves” is disclosed in a Korean patent application assigned Application No. 10-2000-0001881.
FIG. 1 is a perspective view and a sectional view illustrating the structure of the coating liquid drying apparatus using microwaves according to the conventional art. The apparatus is installed on a moving path of an object to be coated in coating equipment for continuously forming coating layers on the surface of an object, and comprises a box-type housing 3, at least one magnetron 1 installed on the housing 3 for radiating microwaves into the housing 3, a power supply unit 14 and a controller 15 for driving and controlling the operation of the magnetron 1 installed outside the housing 3, a pull-in unit 17 and a pull-out unit 18 installed inside and outside an entrance of the housing 3 and having a microwaves shielding film 11 therein, and an air ventilation fan 12 and an air ventilation pipe for exhausting vapors and volatile solvents from coating liquid when drying the coating liquid.
The coating liquid drying apparatus according to the conventional art radiates microwaves on the coating liquid like a flashlight, so that there is a dead zone in which microwaves do not reach the object to be dried, and thereby it has low drying efficiency. Accordingly, it is difficult to dry food waste containing a large amount of water.